As a kind of an arcade game machine, there is known that one for performing a poker game on a video screen. In this kind of the game machine, a predetermined number of cards are distributed to a player as a hand (typically, five cards) on a screen, and if a combination set as a lucky hand is included in the above hand, a player wins and a predetermined dividend is given to the player. A total of 53 cards is used in the game similarly to in the actual trump game, including one joker and four suits; hearts, diamonds, clubs, and spades respectively consisting of 13 cards. A probability of selecting each card is evenly set in the four suits. Accordingly, a probability of completing a lucky hand of the poker is the same as that in the general game.
In the above-mentioned game system, there are some systems of producing a probability fluctuation mode in which a probability of completing a lucky hand is increased if a predetermined condition is satisfied. When it enters into the probability fluctuation mode, a player can get a large amount of dividend. Therefore, a game system with the probability fluctuation mode can enhance the player's expectation for a greatest hit as well as attract the player's fun extremely.
In the conventional game system, however, the number of the cards used in a game remains as it is and a probability of producing a lucky hand is increased by varying the calculation in deciding the cards that a computer distributes to a player. In this case, there may occur a change such as continuous occurrence of a lucky hand or easy occurrence of a lucky hand which would be ordinarily hard to complete. This may cause a player to feel unnatural in the outcome of a game and spoil the player's interest in the game.